Central clutch releases for hydraulic clutch actuation are known, in particular for dual-clutch transmissions, in which the cylinder housing is made of a plastic. A cylinder wall of the cylinder housing delimits an annular pressure chamber radially toward the outside, in which a ring piston which is operationally connected to the clutch is movably accommodated. In this case, the cylinder housing is formed of two cylinder walls arranged concentrically to each other, where the inner cylinder wall forms the boundary of the pressure chamber and is referred to as a guide sleeve.
In operating states of the slave cylinder, in particular at the boundary zone of the forces and beyond, it may be that the clutch release bearing loses the partner for power transmission, preferably the diaphragm spring of the clutch. At the same time it must be ensured that the release unit is not able to travel beyond the specified maximum extension, which is guaranteed by a stop anchored on the cylinder housing. If this cannot be guaranteed, the slave cylinder will destroy itself and cause consequential damage. In addition to the strong forces occurring in the slave cylinder during operation of the clutch actuating system, thermal stress occurs.
It is known to use a sheet metal ring as a transport stop for a slave cylinder of the clutch actuating device. The shaft of this sheet metal ring is flanged in an undercut in the cylinder housing. A sheet metal ring of this sort functions only as a transport restraint, and is designed for the stresses that develop during transport from the manufacturer of the clutch actuating device to the recipient, and prevents breakup of the slave cylinder during transport.
Thus there exists a long felt need for a simply and economically producible piston-cylinder arrangement which has a stop for the piston that stands up both to the pressures which occur in operation of the clutch actuating device and to the thermal stresses.